Except as provided in GPM 602.2, Pre-Award Costs, GPM 602.3, Post-Expiration Costs,or GPM 617, Publication, Documentation and Dissemination, expenditures may not be charged prior to the effective date or subsequent to the expiration date under an NSF cost reimbursement grant.
The ODF file extension is known as OpenDocument Formula which was created by OpenOffice.org Math. It is a file format that saves the text used for creating the formula as well as mathematical equation. Formatted results can be printed to a .pdf file. They are based on the OASIS OpenDocument standard.
OVF packages are often described as an OVF file, but it's more of a package. An OVF package is a collection of multiple files within a directory. One file is the .ovf file, which is an XML descriptor that outlines the package's metadata such as name, hardware requirements and references to other files within the package. Disk images and certificate files are also contained in an OVF package.